Yazar "Erulas, Fatih" seçeneğine göre listele

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    A green, accurate and sensitive analytical method based on vortex assisted deep eutectic solvent-liquid phase microextraction for the determination of cobalt by slotted quartz tube flame atomic absorption spectrometry
    (Elsevier Sci Ltd, 2020) Tekin, Zeynep; Unutkan, Tugce; Erulas, Fatih; Bakirdere, Emine Gulhan; Bakirdere, Sezgin
    Preconcentration of cobalt was carried out with deep eutectic solvent based liquid phase microextraction (DES-LPME) for trace determination by a slotted quartz tube (SQT) attached flame atomic absorption spectrometry (FAAS) system. Choline chloride and phenol in a 1:2 M ratio was used as a green solvent to extract cobalt from the aqueous sample solution. Key parameters influencing the extraction efficiency of cobalt were examined and optimized. Under the conditions optimized, the linear dynamic range was found between 5.0 and 50 mu g L-1, and the limits of detection and quantification (LOD and LOQ) were calculated as 2.0 and 6.6 mu g L-1, respectively. The detection power of the conventional FAAS was improved upon by 67 folds using the optimized DES-LPMESQT-FAAS method. The developed analytical method was successfully applied for the determination of cobalt in linden tea samples and the recovery results obtained for different spiked concentrations (20, 30 and 40 mu g L-1) were remarkable (approximate to 100%).
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    A novel liquid-liquid extraction for the determination of naphthalene by GC-MS with deuterated anthracene as internal standard
    (Springer, 2017) Erarpat, Sezin; Ozzeybek, Gozde; Chormey, Dotse Selali; Erulas, Fatih; Turak, Fatma; Bakirdere, Sezgin
    Polycyclic aromatic hydrocarbons are known for their carcinogenic and mutagenic effects on human health. This therefore calls for the regulation of their concentrations in air, water, and soil. Naphthalene as the simplest in structure of the polycyclic aromatic hydrocarbons is mainly used as a starter material for other chemicals but also has impacts on human health. A method is therefore proposed for the determination of naphthalene in water samples by gas chromatography mass spectrometry after liquid-liquid extraction. The extraction method was optimized to improve the extraction output, thereby lowering the limit of detection. The limits of detection and quantification obtained for naphthalene were 4.4 and 14.6 ng mL(-1), respectively. Deuterated anthracene was used as internal standard to enhance the precision of the method, for which a relative standard deviation of 4.3% was obtained. The percent recovery of naphthalene obtained from tap water was ranged between 93.8 and 102.2.
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    Accurate and simple determination of oxcarbazepine in human plasma and urine samples using switchable-hydrophilicity solvent in GC-MS
    (Wiley, 2020) Erarpat, Sezin; Bodur, Suleyman; Ayyildiz, Merve Firat; Gunkara, Omer Tahir; Erulas, Fatih; Chormey, Dotse Selali; Turak, Fatma
    This work presents a sensitive and rapid analytical method for the determination of oxcarbazepine in human plasma and urine samples. A vortex-assisted switchable hydrophilicity solvent-based liquid phase microextraction (VA-SHS-LPME) was used to preconcentrate oxcarbazepine from the samples before the determination by gas chromatography mass spectrometry. The switchable hydrophilicity solvent was synthesized by protonatingN,N-dimethylbenzylamine with carbon dioxide to make it totally miscible with an equivalent volume of water. Parameters of the VA-SHS-LPME method including volume of switchable hydrophilicity solvent, concentration/volume of sodium hydroxide and vortex period were systematically optimized. Under the optimum conditions, good linearity ranging from 27.03 to 353.47 mu g/kg was obtained for the analyte. Limit of detection and quantitation values were found to be 6.2 and 21 mu g/kg (mass base), respectively. The relative standard deviation was calculated as 6.9% for six replicate measurements of the lowest concentration of the calibration plot. Satisfactory recovery results were calculated in the range of 97-100% for human plasma and urine samples spiked at five different concentrations.
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    Accurate determination of pesticides, hormones and endocrine disruptor compounds in complex environmental samples using matrix dilution and matrix matching with dispersive liquid-liquid microextraction
    (Walter De Gruyter Gmbh, 2018) Chormey, Dotse Selali; Firat, Merve; Buyukpinar, Cagdas; Erulas, Fatih; Komesli, Okan Tarik; Turak, Fatma; Bakirdere, Sezgin
    Quantitative determination of contaminants in environmental samples is usually hampered by low analyte recovery which results from the complex nature of the sample matrix. This study presents the application of a developed dispersive liquid-liquid microextraction method for the determination of 12 analytes in environmental samples including sea water, fresh water (lake, well and tap water), brackish water and soil samples. Matrix matched standards were used to compensate for the low analyte recovery recorded by the conventional calibration method. The effect of matrix dilution on analyte recovery was also tested. All matrix matched and matrix diluted spiked recoveries were done concurrently with calibration standards prepared in deionized water. Percent recoveries recorded for the analytes according to deionized water calibration standards ranged between 66 and 137 %. Matrix matching and matrix dilution yielded close to 100 % recovery results, but the later lowered the detection limit according to the dilution factor.
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    Arsenic speciation in water and biota samples at trace levels by ion chromatography inductively coupled plasma-mass spectrometry
    (Taylor & Francis Ltd, 2017) Firat, Merve; Bakirdere, Sezgin; Sel, Sabriye; Chormey, Dotse Selali; Elkiran, Omer; Erulas, Fatih; Turak, Fatma
    A sensitive, reliable, simple and rapid analytical method was developed for the determination of arsenite [As(III)], arsenate [As(V)] and arsenobetaine (AsB) species using ion chromatography combined with inductively coupled plasma-mass spectrometry (IC-ICP-MS). Inorganic and organic arsenic species were separated with an anion exchange column (Dionex AS9) and a 50mM sodium bicarbonate mobile phase (pH 10) at a flow rate of 1.0mL min(-1.) %RSD values were found to be lower than 5.1% for all arsenic species. The limits of detection (LOD) obtained for As(III), As(V) and AsB were 16.5 ng L-1, 14.1 ng L-1 and 6.2 ng L-1, respectively. The developed analytical method was tested using AsB certified reference material (NMIJ CRM 7901-a), and spring water certified reference material (UME CRM 1201) for accuracy check. This method was applied for the quantitative determination of arsenic species in different water samples and chicken samples as a solid matrix.